Update on October 12: Bobbi Kristina Brown's rep denies that the teen and Nick Gordon are engaged, but adds, "You have to watch the show!"

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It’s a ring fit for a princess! So it makes sense that it should decorate the fingers of both Kate Middleton and the daughter of the “Queen of the Night,” Whitney Houston. It was revealed today that Bobbi Kristina Brown, 19, is indeed engaged to Nick Gordon, who the late singer raised as her son. On Twitter, Bobbi Kristina posted a photo of the bling her 22-year-old beau gave her: a 15-carat sapphire stunner surrounded by 1.5 carats of diamonds that may look a little familiar … like the one that adorns the hand of Prince William’s wife!

“It’s a definite copy of her ring,” Anthony Sarkissian of Premier Jewelry Lenders in Beverly Hills tells omg!. “The shape of the stone, the way it’s set, having it made in platinum, the thinness of the shank … it’s a carbon copy of [Kate’s ring].”

Bobbi Kristina’s is just a teeny bit smaller. Kate’s sapphire, which once belonged to Princess Diana, is 18 carats. The teen’s version could be worth anywhere from $50,000 to $100,000, depending on its oval-cut center stone. Sarkissian explains that some sapphires are heated in order to give them a more brilliant blue color, yet it’s impossible to judge Bobbi Kristina’s based solely on a photo of the gem. He adds that the round-cut diamonds surrounding the sapphire add approximately another $10,000 to the ring’s worth. It’s unclear how Gordon, who ostensibly does not work, could afford such a pricey rock.

Colored stones like sapphires, emeralds, and rubies have become very popular in recent years, thanks to Middleton, Jessica Simpson, and Halle Berry – although “generally it’s done on a smaller scale, like a 3-5 carat sapphire and a half a carat of diamonds around it,” says Sarkissian. Still, given Bobbi Kristina’s age, “to have one of this size is a bit ridiculous, but I guess in today’s era anything is possible.”

Bobbi Kristina and Gordon, who began dating immediately after Houston’s February death, announced their engagement to her family in a new clip to promote their E! reality show, “The Houston’s On Our Own,” which premieres on October 24. In the preview, Houston’s brother Gary confronts Gordon, saying, “No one knew that from a godson you would turn into a boyfriend,” to which Gordon retorts, "Nobody has to be in my business."

After Houston’s death, Bobbi Kristina was spotted wearing her mother’s diamond ring, which initially sparked rumors that she and Gordon were engaged. In recent photos posted on Bobbi Kristina’s Twitter page, she wears the sapphire on her left hand and her late mother’s diamond on her right.